The present invention relates to an information processing apparatus used as the so-called authoring tool for creating broadcast contents such as MHEG (Multimedia Hypermedia Information Coding Expert Group) contents to be broadcasted along with video information.
In recent years, digital satellite broadcasting has become popular. In comparison with the contemporary analog broadcasting, for example, digital satellite broadcasting is better at preventing noise and fading, hence, is capable of transmitting a signal with a high quality. In addition, the frequency utilization rate is improved and a multi-channel transmission can also be embraced. To put it concretely, in the case of digital satellite broadcasting, several hundreds of channels can be preserved by using one satellite. In such digital satellite broadcasting, it is possible to provide a number of special channels such as channels for sports, movies, music and news. Programs for special plans and contents of the channels are broadcasted through their respective channels.
By utilizing such a digital broadcasting system, the user is capable of downloading musical data such as a piece of music. There also has been proposed a system, called television shopping, that allows the user to make a purchasing contract to buy some products while watching a broadcast screen. That is to say, the digital satellite broadcasting system broadcasts additional data services at the same time as an ordinary broadcast program.
In the case of an operation to download musical data, for example, the broadcasting station broadcasts the musical data by multiplexing the data so as to synchronize the data with a broadcast program or video information. In addition, the user is capable of carrying out downloading operations interactively while watching a displayed GUI (Graphical User Interface) screen which serves as a downloading operation screen. Data for displaying such a GUI screen is also broadcasted by multiplexing.
Then, the user owning a reception apparatus selects a desired channel to display a GUI screen for downloading musical data by carrying out a predetermined operation on the reception apparatus. The user then carries out an operation on the GUI screen typically to supply the musical data to a digital audio apparatus connected to the reception apparatus. Typically, the musical data is recorded in the digital audio apparatus.
Incidentally, with regard to a GUI screen for downloading musical data described above, partial picture data and text data which are used as elements to form the GUI screen and unit data (or files) such as audio data to be output as a sound in accordance with a predetermined operation are each handled as an object. The output format of an object is controlled by a scenario description according to a predetermined system. That is to say, by broadcasting the so-called multimedia contents, a GUI screen described above is implemented.
It should be noted that a GUI screen for implementing a function to achieve a certain objective by prescription of described information is referred to as a “scene”. A scene also includes an output such as a sound. An “object” is defined as unit information such as a picture, a sound or a text with an output format thereof prescribed on the basis of described information. In addition, during transmission, a data file of described information itself is also handled as one of the objects.
For example, as a system to prescribe a description of a content for broadcasting a GUI screen like the one described above, adoption of an MHEG system is conceivable.
In an MHEG prescription, one MHEG content or one MHEG application file typically comprises one or more scenes. A script is described to prescribe transitions between scenes and outputs which are synchronized with typically broadcast pictures of the scenes. In addition, a scene is controlled by a description of a script so that one or more objects of the scene are displayed in a predetermined display format.
In the broadcasting station, the MHEG content described above is created in accordance with broadcast contents by using typically a personal computer. On the personal computer, application software used as the script creation tool or an authoring tool is activated. Such application software is referred to hereafter as an MHEG authoring tool, a generic name given to the software.
Editing work is carried out typically in scene units by using the MHEG authoring tool described above. In general, objects to be displayed for a scene are selected and the editor writes a description of a scenario so as to display the selected objects in desired display formats in the scene. As an alternative, a GUI screen is used as the authoring tool to create a scene and editing results are described as a script.
Incidentally, a concept known as a shared object is prescribed in an MHEG application.
A shared object is a file used as an object which is shared among scenes.
With the contemporary MHEG authoring tool, however, there is provided only a function of merely selecting whether to use or not use a shared object for an MHEG application unit. To put it in detail, it is possible only to select an option to display or not to display a shared object as an object common to all scenes comprising an MHEG application.
Consider an attempt to effectively utilize a shared object. In this case, it is desirable to set any arbitrary shared object to be used or not to be used in each of scenes comprising an MHEG application.
If any arbitrary shared object is to be assigned to a scene instead of being assigned to an MHEG application, the option of using or the option of not using a shared object in a scene must be set by using typically a description of an action to turn on or off individual objects created for the object.
In order to set the option by using a description of such a script, it is necessary for the editor to sufficiently understand the description language. Thus, setting the option is a difficult job for the editor. In the end, it is quite within the bounds of possibility that the editor writes an incorrect description. For this reason, almost no editors use such a description to assign any arbitrary shared object to a scene in place of an MHEG application.
In consequence, shared objects are not utilized effectively in the present state of the art. As a result, there are hindrances to diversification of display formats of MHEG contents.